心脏和肾脏短暂缺血对心肌保护作用的比较研究

Comparative study on myocardial protection provided by myocardial and renal ischemic preconditioning

目的 明确心脏和肾脏短暂缺血预处理对心肌缺血 再灌注 (MIR)所致心肌坏死和细胞凋亡的影响。方法 在家兔MIR模型上 ,36只动物随机分为单纯MIR组、心肌短暂缺血预处理 (MIP)组和肾脏短暂缺血预处理 (RIP)组。实验过程中 ,记录血流动力学、心外膜电图 ;应用三苯硝基四氮唑红测定心肌梗死范围 ;采用末端标记和流式细胞方法检测心肌细胞凋亡等。结果 (1)血流动力学和心外膜电图 :三组动物的血流动力学指标在MIR过程中逐渐下降 ;心外膜电图ST段在缺血期明显抬高 ,再灌注过程中恢复正常。 (2 )心肌梗死范围 :MIR组的心肌梗死范围 (坏死区占缺血区的重量百分比 )为 (5 3 83± 2 0 4 ) % ,MIP组和RIP组的心肌梗死范围分别为 (2 9 6 7± 2 16 ) %和 (33 0 0±3 4 6 ) %。与MIR组相比 ,MIP组和RIP组的心肌梗死范围明显减小 (P <0 0 1)。 (3)心肌细胞凋亡 :末端标记显示 ,MIR组、MIP组和RIP组中缺血区的心肌细胞凋亡率分别为 (10 98± 0 92 ) %、(5 93±0 81%和 (5 5 8± 0 5 0 ) % ,MIP组和RIP组缺血区中的细胞凋亡率较MIR组明显降低 (P <0 0 1)。结论 MIP和RIP均能减少MIR所致的心肌梗死范围和细胞凋亡 ,MIP和RIP对心脏的保护效应无明显差别。

Objective To determine the effect of myocardial ischemic preconditioning (MIP) and renal ischemic preconditioning (RIP) on myocardial infarct size and apoptosis induced by myocardial ischemia reperfusion (MIR) Methods In rabbit MIR models, 36 animals were randomized into the simple MIR, MIP and RIP groups The hemodynamics and epicardial electrography were recorded, myocardial infarct size was examined with triphenyl tetrazolium chloride,and apoptosis was detected in situ with end labeling method and measured by flow cytometry Results (1) During the course of MIR, heart rate, blood pressure and myocardial oxygen consumption decreased progressively The epicardial electrographic ST segment was elevated significantly during ischemia, and recovered to baseline during reperfusion (2) The myocardial infarct size, expressed as a percent of the ischemic myocardium was (53 83±2 04)%, the infarct sizes in MIP and RIP groups were significantly reduced to (29 67±2 16)% and (33 00±3 46)% respectively( P <0 01) (3) Apoptotic cardiomyocytes were sparse within ischemic myocardium at risk in MIP and RIP groups as compared with that in MIR group in situ end labeling method Apoptosis rates in ischemic myocardium from MIR, MIP and RIP groups detected by flow cytometry were (10 98±0 92)%,(5 93±0 81)% and (5 58±0 50)% respectively, and the apoptosis rate in ischemic myocardium from MIR group was higher than that from MIP and RIP groups( P <0 01) Conclusion Both MIP and RIP could reduce myocardial infarct size and apoptosis induced by MIR The myocardial protection of MIP and RIP was not significantly difference